Despite advances in co-integration of electronics and photonics on the same substrate in silicon substrate, the implementation cost of optical communication channels remains an impediment to broad deployment of high speed optical systems for short range front-end of communication networks.
Active optical cables have become widely available in data centers and high performance computing clusters. The main bottleneck limiting the data rate in such cables is the bandwidth of the electro-optical components, such as the optical modulator and photodiodes.
The proliferation of high bandwidth applications such as streaming video has resulted in high demand for faster data communication. Copper based communication channels are being replaced with superior optical fiber channels that provide more bandwidth. As a result, the communication speed bottleneck is moving from communication channel to the electro-optical interfaces.
One technique to compensate for copper channel bandwidth limitation and to mitigate the limited bandwidth of electro-optical components is equalization. While integrated electronic circuits continue to operate at higher speeds, they still face challenges in keeping up with the bandwidth required for equalization.